CVE-2026-66729

facil.io 0.6.0 through 0.7.6 contains an integer underflow vulnerability in the multipart MIME body parser that allows unauthenticated remote attackers to crash the server process by sending a crafted Content-Disposition header with an empty field name. Attackers can trigger a uint32_t wraparound in http_mime_parser.h causing an out-of-bounds memory read past the name pointer, resulting in a bus fault that crashes the handling worker with a single POST request.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/theopaid/Out-of-Bounds-Read-in-facil.io-MIME-Parser-leads-to-Server-Crash
https://tpaidakis.com/writeups/facilio-parser-dos/
https://www.vulncheck.com/advisories/facil-io-integer-underflow-dos-via-multipart-mime-body-parser

Configurations

No configuration.

History

No history.

Information

Published : 2026-07-27 17:16

Updated : 2026-07-31 19:17

NVD link : CVE-2026-66729

Mitre link : CVE-2026-66729

CVE.ORG link : CVE-2026-66729

JSON object : View

Products Affected

No product.

CWE

CWE-125

Out-of-bounds Read

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